Since early 2001, Kalgoorlie Consolidated Gold Mines (KCGM) has successfully operated an ultra fine grinding (UFG) circuit to supplement its roaster capacity for the treatment of the refractory gold flotation concentrate. A second UFG mill was installed in 2002 taking the total UFG capacity to over 20tph while grinding to 11-12 microns and achieving over 90% gold recovery.
The current high gold price is increasing the focus on the development of refractory gold ores and concentrates. Outotec can deliver the three main oxidative processes for the treatment of refractory gold concentrates – BIOX, pressure oxidation, and roasting – and also supply equipment for ultra-fine grinding as a fourth, non ...
1. Introduction. Gold ore is referred to as refractory when gold extraction in a direct cyanidation process is less than 80%, even after fine grinding [].In other words, gold ore is refractory when the metal of interest cannot be optimally recovered by conventional methods ().
Ultra-fine gold particles can be trapped within the mineral matrix, even at extremely fine grind sizes. Three primary factors cause gold to be considered refractory. Each factor needs to be addressed with a different type of pre-treatment before …
Ultra Fine Grinding Some refractory ores such as those containing pyritic gold can benefit from very fine grinding prior to cyanidation. Several technologies including IsaMillTM, Verti-mill and Stirred Media Detritor (SMD), Deswik, and Metprotech are available to grind ores or concentrates to as fine as 2-3µm to liberate
Leachox, Ultra fine grinding, Vasilkovskoye, Refractory, Imhoflot pneumatic flotation, Leaching, Oxidation . ABSTRACT . The Leachox refractory gold process has to date been applied to the selectivetreatment of several refractory gold ores but on a …
1. I N T R O D U C T I O N 1.1 Refractoriness Gold ores are considered refractory if gold extractions from a conventional cyanidation process are less than 80% even after fine grinding [ 1 ]. These low extractions do not normally allow economic recovery of the metal [2-6].
Abstract: Gold telluride ores are important gold refractory ores due to the presence of sulfides and other gangue materials. The classification ... Australia). As mentioned above, fine grinding, the extension of leach residence time or the excessive addition of lime has been used to overcome the refractory nature of tellurides.
Refractoriness (the degree of resistance to standard recovery methods) is generally due to total encapsulation of extremely fine gold particles by a host mineral that is …
Minerals Engineering, Vol. 4, Nos 7-11, pp. 763-776, 1991 0892-6875191 $3.00 + 000 Printed in Great Britain Pergamon Press plc ULTRA FINE MILLING FOR THE RECOVERY OF REFRACTORY GOLD I.J. CORRANS and J.E. ANGOVE Ammtec Pty Ltd, 6 Macadam Place, Balcatta, WA 6021, Australia ABSTRACT Refractory gold ores may be defined as those …
refractory sulphide portion of the Salmon deposits. The test work assessed the merits of producing a flotation concentrate followed by ultra-fine grinding, LeachOx, BIOX, or pressure oxidation. A sulphide resource estimate and preliminary economic assessment were prepared
Refractory gold ore, which shows poor gold recovery by cyanidation, typically contains one or all of the following: (1) carbonaceous matter (C-matter), which causes preg-robbing; (2) locked gold in sulfides/silicates, and (3) cyanide/oxygen consumable matter, such as copper or sulfidic material [1,2,3].The ore used in this study is typical refractory gold …
Refractory gold processing through preconcentration, fine grinding, leaching or oxidation. Desorption circuit specification and operation such as AARL, Merrill Crowe as well as electrowinning cell operations, current density, sludging cells operations and carbon regeneration. Goldroom operations and smelting.
Refractory Gold Any ore that is not readily amenable to recovery by conventional cyanide leaching at a reasonable grind size can be considered refractory. The three primary factors that cause gold ores to be refractory are: Physical encapsulation – Extremely fine (<10 µm) particles are locked within an impervious, unreactive mineral.
Grinding refractory gold ores to below 20 microns and finer, whilst liberating more gold, also liberates many other mineral species which affect the oxidative and cyanide downstream process. In many cases when only ultra fine grinding is used a maximum recovery is reached and grinding finer actually reduces the precious metal recovery.
This laboratory work presents a study of the effect of ultrafine grinding on the gold recovery of a highly refractory gold concentrate. The particle size of the concentrate was P 80 = 46 µm and the main species present were quartz (28.58%), dolomite (25.63%), pyrite (20.93%), arsenopyrite (15.39%) and 112 g/t gold. After optimizing hydrated lime and lead …
Refractory Gold. Any ore that is not readily amenable to recovery by conventional cyanide leaching at a reasonable grind size can be considered refractory. The three primary factors that cause gold ores to be refractory are: • Physical encapsulation – Extremely fine (<10 µm) particles are locked within an impervious, unreactive mineral.
It is very important to define well, what kind of refractoriness it is, is it physical, chemical or due to carbonaceous materials. Mineralogy will be able to help and from those results different methods may be used. Physical fine grinding can deal with invisible gold by milling up to the size of the gold grains an actually energy intensive ...
Since early 2001, Kalgoorlie Consolidated Gold Mines (KCGM) has successfully operated an ultra fine grinding (UFG) circuit to supplement its roaster capacity for the treatment of …
leaching with cyanide. Gold recovery is usually around 80%, but can be as low as 60%. Recoveries can be improved to 95-99% by grinding to fairly fine particle size, gravity separation, cyanidation and flotation, all of which increase capital and operating costs. In some cases, oxidation of sulphide minerals is needed to liberate gold that
The application of ultra fine grinding to refractory gold ores or concentrates has proven to offer a viable alternative to conventional oxidative processes. Many gold plants have effectively used the stirred mills including IsaMill ® and SMD ® mills for ultra fine grinding,,, .
KEY WORDS: arsenic-bearing gold ore; pretreatment process; refractory gold ore. 1. Introduction Gold ores are considered refractory if gold extractions from a conventional cyanidation process are less than 80% even after fine grinding.1) Arsenic-bearing refractory gold ore has stones extremely difficult to deal with. In the stones,
The so-called refractory gold ore refers to the ore and concentrate that can not obtain satisfactory leaching rate by direct extraction of gold by traditional cyanidation under normal grinding conditions. It is also called refractory gold ore or refractory gold ore.
The Refractory Gold Project process flow consisted of two stage crushing and ball milling followed by an ultra-fine grind and afloatation circuit for concentration of the gold. Flotation concentrate is oxidised through reactors and processed in a standard gold CIL circuit from where the loaded carbon is harvested and gold recovered through ...
Initially, Jerritt Canyon was designed to process oxide and mildly refractory gold ores. In 1989, the roasting circuit was added to the process for the treatment of highly refractory ores which are now being mined and processed at Jerritt Canyon. ... which is then conveyed to a 2,000 ton fine ore bin that feeds the dry grinding circuit. The dry ...
Free Milling Gold is the gold that can be liberated by a standard rotating ball mill. Refractory Gold is that which is not recoverable by standard milling and/or chemical processes. This may be 'entrapped in sulfides'. A standard ball mill may grind your ore to 75 microns. Fine grinding is one process available to liberate refractory gold.
Gold ores are considered refractory if gold extractions from a conventional cyanidation process are less than 80% even after fine grinding. 1) Arsenic-bearing refractory gold ore has stones extremely difficult to deal with. In the stones, gold is locked up in arsenic mineral matrix as the form of microscopic or submicroscopic lattice.
options for refractory gold ores: roasting; pressure oxidation; bio-oxidation; and ultra-fine grinding. In roasting, pressure oxidation and bio-oxidation, the iron sulphide minerals are oxidised to create sulphur dioxide (SO 2) gas in the case of roasting, or sulphate ions in pressure oxidation and bio-oxidation. The iron component is
Ball mill, also called grinding mill, ball grinding mill, is the key equipment to grind crushed materials into fine powder 20-75 micrometer. It has grate type and overflow type. ≤25mm Feed Size. 18.5-800KW Motor Power. 0.62–90 t/h Processing capacity.
Ultra-fine gold particles can be trapped within the mineral matrix, even at extremely fine grind sizes. Three primary factors cause gold to be considered refractory. Each factor needs to be addressed with a different type of pre-treatment before gold can be recovered by conventional cyanidation. These factors are physical encapsulation ...
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